Rapid start-up / restart avionics provide robust fault tolerance with reduced Size, Weight And Power

An approach that uses rapid start-up computers to provide fault-tolerance and transient upset recovery while minimizing Size, Weight and Power (SWaP) is described. ^{1 2} This paper provides a status report on a research project conducted by Draper Laboratory aimed at developing avionics suitable for both manned and unmanned space vehicles. They are intended to provide extremely high levels of reliability but with reduced SWaP as compared to current systems. The key to this is the ability to very rapidly power-up back-up hardware and to start up or restart software. A handoff of uncorrupted state data from the failing computer to the start-up or restart computer is also required. All fault-tolerant avionics require the use of redundant components to take over in the event of a component failure. Typical practice for critical and real-time control systems is to keep the redundant components powered and ready to instantly take-over in the event of failure. This proven approach works well but increases the power consumption of the avionics, increasing vehicle battery or power generation size and mass and requires additional thermal control measures to remove avionics heat. It is also typical practice to address transient fault conditions by using additional powered redundancy to instantly assume control during transients. The added redundancy needed to maintain control during transients also increases SWaP. Substantial reductions in power consumption can be realized if redundancy is only powered in response to a failures or transient upsets.